Make friends with your classmates, they will end up being like family and will be invaluable in the coming years. Since a lot of programs are very competitive to get into many people enter with that mindset but you'll be most successful and happiest if you're working as a team. Wether you have a rough ay at clinicals, struggle with a subject or anything, they're going to be the ones literally going through poo with you! As far as school, don't worry about studying much before the program starts, you'll be fine. Enjoy your summer and good luck!